Method of manufacturing rubber articles



l atente cl Mar. 24, 1931 I f UNITED STATES EDWIN 2B. NEWTON, or

AKRON, OI-IIO, nssicmonmo AMERICAN ANODE, ive, on Anson, j

OHIO, A CORPORATION on, n nnw ae METHOD or MANUFACTURING gusse Anricn i i 1 Io Drawing, Application filed March 6,

.This invention relates to the artof manufacturing rubber, and particularly to methods' formanufacturing rubber articles containing two superimposed, adherent layers.

a Rubber articles must frequently be made from two or more different layers, which are superimposed and vulcanized together to form an integral whole. Often the layers must exhibit different properties and are 0,; made of different rubber compositions.

2.0 and is further reinforced by fabric inserts.

For example, an automobile tire contains a stiff wear-resisting tread composition, a soft cushion composition under the tread, and a tough elastic composition surrounding the cords of the carcass. The inner tube is made from a soft and elastic, but strong and tough, composition, while the valve padattached thereto is made from a firm composition to resist cutting and'tearing by the valve stem,

Certain typesof rubber compositions may be prepared very economically and of a surpassingly high quality directly from latex or similar rubber emulsions, the latexcona 7 until it is plastic, and then mechanically adl dients, etc.

taining the necessary vulcanizing ingredients, fillers, etc. 111 suspension. .Other com-V positions, however, are best prepared from rubber which is -masticated and kneaded mixed with the requisite vulcanizing ingre Such masticated rubber has a very sticky or tacky surface before" Vulcan 'ization complete. articles being, readily-built upbysuperimposing the constituent parts, which adhere quitefirmly,even' in the unvulcanized condition; Rubber which is derived directly from rlatex',- without mastication,

chemical depolymerization, or othersimilar process, whether formed by electrodeposi: tion, coagulation, dessication, or any other process, lacks'the tackiness of the masticated rubber and does not satisfactorily adhere, in the unvulcanized condition, to masticated' rubber surfaces.

o I have discovered that unvulcani'zed masticated rubber and unmasticated latex rubber 1 may be caused to adhere firmly,vone to the other, even before vulcanization, by superimposing the two layers after the latex rubber has been coagulated but'before it is dry. 7

'vulcanize at the same rate as thednnertube 1929. Serial No. 344,929.

The, composite product subsequently dried and vulcanized, whereupon the union be- I tween the two layers madeper-manent. 1 I

For example, inthe manufacture of innertubes. directly from latex, the latex-is adis strengthened and mixed with the requisite proportions ofasul-fl phur, acceleratoran'd other desirable: addi-q tions, and is coagulated in substantially the ultimate shape which it. s is, to assume. The

sition on a g conducting mandrel immersed inthe latexcoinposigtion, but it will be understood that-other methods of coagulation may likewise be, employed. The valve padfwhich is; to be afiixedto-the inner tube ismanufactured in the well known'mannenbyad mixing rubberby mastication with thequan titys' of sulphur, accelerator, etc. which will proper, and formingthe' plastic admixture by calendaring or other convenient means coagulation may beinduced byaelectro-depqinto a pad reinforced with one., or more. layers of fabric. ,The said pad is thereupon aifixed; to the coagulated wet, inner tube andpressed firmly into place. The pad adheres so firmly to the. 'wet'latex rubber that vit cannot. be removed therefrom Without greatly-damaging 'or'tearing therubber; lfdesired, a portion therewith. Theftapa is removedf the' tube" dried,,and vulcanizedgby heating in steam or hot water for the required length of time.

It" is obvious that themethodf of this in- Vention is notflimited to the example der l v 95 in which it slsnecessar-y or-desirable to adhere scribed above, but is: applicable inany case a layervof,"masticated; rubberto a layer of unmasti'cated. rubherdirectlyderived; from. latex. It is therefore to V be understood: that it is notlintended to limit the scope ofthis 'inr- 1;:

vention except as may be required by the the latex rubber, and drying and vulcanizing prior art and as indicated in the appended the tube.

claims. v In witness whereof I have hereunto Set I claim: my hand this 2nd day of March, 1929. 5 l. The method of manufacturing'com- EDWIN B. NEWTON. 7G

posite rubber articles which comprises superimposing a layer of plastic masticated rubber and a layer of coagulated wet latexrubber.

10' 2. The 'method of manufacturing com 'posite rubber articles which comprises superimposing a layer of plastic masticated rubber and a layer of coagulated wet latex rubber and uniting the layers by pressure. Y Y 3. The method of manufacturing compos- 8o ite rubber articles which comprises forming the elements thereof respectively from plastic masticated rubber and from latex by c0- a ulation, and uniting the said "elements 2o ,W%1il8 the coagulated latex rubber is still wet. y 1 Y 85 4. The method of manufacturing composite rubber articles which comprises forming the elements thereof respectivelyfrom plastic masticated' rubber and from latex by coagulation, uniting the said elements while the coagulated latex rubber is still wet, and applying pressure to express a portion of the water from the latex rubber and to promote the union of the respective elements. a Y 5. The method of manufacturing composite rubber articles which comprises forming the elements thereof respectively from plastic masticat'ed rubber and from latex by coagulation, uniting the said elements while the latex rubber-is still wet, and drying and Y 100 vulcanizing the articles. v Y Y 6. The method of manufacturing inner tubes which comprises forming a tube from latex by coagulation thereof, and aflixing a Y r H Y 40 valve pad of plastic, masticated rubbervto' Q Y ms the wet, coagulated tube. I Y V Y 7 The method of manufacturing inner tubes which comprises forming a tube from latex by coagulation thereof, affixing a valve Y i Y Y pad of plastic, masticated rubber to the wet, Y I

coagulated tube, and applying a substan-- tially uniform pressure to the surface of'the tube to express a portion of the water therefrom and promote the union of the valve pad with the latex rubber.

' the tube. I Y

9. The method of manufacturing inner tubeswhich comprises forming a'tube from V i Y v latex by coagulation thereof, aflixing a valve Y 1'25 pad of-plastic, masticated rubber to the .wet, coagulated tube, applying 'a substantially uniform pressure to-the surface of the'tube to'express a portion of the water therefrom Y Y 1 g 5 and promote the union of the valve pad with g 3 8. The method of manufacturing inner tubes which comprises forming a tube from latex by coagulation thereof, affixing a valve pad of plastic, masticated rubber to the Wet Q coagulated tube, and drying and vulcanizing v 12o 

